This invention pertains to fasteners for securing to sheet metal, and more particularly to that type of fastener which may be nailed directly into the sheet metal for attaching such materials as acoustical or thermal insulation without requiring total penetration of the sheet or engaging means in the reverse side.
A sheet metal fastener of this type is shown in U.S. Pat. No. 3,095,777. The disclosed fastener has a pair of opposed taperingly beveled jaws originally spaced from each other, which upon being driven into the sheet are clinched inwardly by their outer beveled surfaces, causing the jaws to grasp a small bulbous fragment of the metal. Close control of the driving force is required, since an excess force causes the jaws to close completely and bite the bulbous fragment entirely off, while an insufficient force results in insufficient clinching.
Fasteners for securing materials to and penetrating through sheet metal are known in the art. According to U.S. Pat. No. 3,645,163, a divided expanding nail type fastener having barbs along its shank pierces the sheet metal; the barbs catch in the reverse side and hold the nail in place.
One type of tubular rivet, used for interpenetrating and fastening together soft material such as leather, is shown in a patent to Bray, No. 180,747. That device comprises a short tubular shank whose end is beveled outwardly. Upon being driven into the leather, the beveled end deflects to clinch the pieces together, possibly splitting as it does so.